Calculating $lim_{x to 0} frac{ln sin(x)}{lntan(x)}$











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I need some help calculating this limit:



$$lim_{x to 0} frac{ln sin(x)}{ln tan(x)}$$










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  • Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
    – 1ENİGMA1
    Nov 16 at 11:50










  • You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
    – Kavi Rama Murthy
    Nov 16 at 11:52






  • 1




    @1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
    – xbh
    Nov 16 at 11:56










  • @xbh I know it. What I mean you can see answers.
    – 1ENİGMA1
    Nov 16 at 12:16















up vote
-1
down vote

favorite












I need some help calculating this limit:



$$lim_{x to 0} frac{ln sin(x)}{ln tan(x)}$$










share|cite|improve this question









New contributor




Lowie is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




















  • Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
    – 1ENİGMA1
    Nov 16 at 11:50










  • You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
    – Kavi Rama Murthy
    Nov 16 at 11:52






  • 1




    @1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
    – xbh
    Nov 16 at 11:56










  • @xbh I know it. What I mean you can see answers.
    – 1ENİGMA1
    Nov 16 at 12:16













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











I need some help calculating this limit:



$$lim_{x to 0} frac{ln sin(x)}{ln tan(x)}$$










share|cite|improve this question









New contributor




Lowie is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I need some help calculating this limit:



$$lim_{x to 0} frac{ln sin(x)}{ln tan(x)}$$







limits






share|cite|improve this question









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Lowie is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question









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edited Nov 16 at 14:02









gimusi

85.5k74294




85.5k74294






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asked Nov 16 at 11:44









Lowie

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Lowie is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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Check out our Code of Conduct.












  • Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
    – 1ENİGMA1
    Nov 16 at 11:50










  • You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
    – Kavi Rama Murthy
    Nov 16 at 11:52






  • 1




    @1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
    – xbh
    Nov 16 at 11:56










  • @xbh I know it. What I mean you can see answers.
    – 1ENİGMA1
    Nov 16 at 12:16


















  • Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
    – 1ENİGMA1
    Nov 16 at 11:50










  • You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
    – Kavi Rama Murthy
    Nov 16 at 11:52






  • 1




    @1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
    – xbh
    Nov 16 at 11:56










  • @xbh I know it. What I mean you can see answers.
    – 1ENİGMA1
    Nov 16 at 12:16
















Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
– 1ENİGMA1
Nov 16 at 11:50




Hint:As can be seen, the point is not in the domain of the function, so the limit does not exist.
– 1ENİGMA1
Nov 16 at 11:50












You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
– Kavi Rama Murthy
Nov 16 at 11:52




You can only take right hand limit. To find the value of the limit you simply have to apply L'Hopital's Rule.
– Kavi Rama Murthy
Nov 16 at 11:52




1




1




@1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
– xbh
Nov 16 at 11:56




@1ENİGMA1 The existence of limits does not depend on whether the function is defined at the point. We only require that the point is a limit point of the domain.
– xbh
Nov 16 at 11:56












@xbh I know it. What I mean you can see answers.
– 1ENİGMA1
Nov 16 at 12:16




@xbh I know it. What I mean you can see answers.
– 1ENİGMA1
Nov 16 at 12:16










3 Answers
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1
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HINT



As noticed we need $x>0$ then



$$frac{ln sin(x)}{ln tan(x)}=frac{ln frac{sin(x)}x+ln x}{ln frac{tan(x)}x+ln x}$$






share|cite|improve this answer




























    up vote
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    Just consider the reciprocal (for $x>0$):



    $$frac{ln tan x}{ln sin x} = frac{ln sin x - ln cos x}{ln sin x} =1- frac{ln cos x}{ln sin x} stackrel{x to 0^+}{longrightarrow} 1$$
    It follows $boxed{lim_{x to 0+} frac{ln sin(x)}{ln tan(x)} = 1}$.






    share|cite|improve this answer






























      up vote
      0
      down vote













      The domain of $ln x$ includes all positive values of $x$, so only the right-hand limit exists. If you want to find that, you can use L’Hôpital’s Rule.



      $$lim_{x to 0} frac{ln(sin x)}{ln(tan x)}$$



      $$implies frac{frac{1}{sin x}cos x}{frac{1}{tan x}sec^2 x} = frac{tan x}{sin x}cdot frac{cos x}{sec^2 x} = frac{1}{cos x}cdot cos^3 x = cos^2 x$$



      Now, what does $cos^2 x$ tend to as $x$ tends to $0$?






      share|cite|improve this answer





















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        3 Answers
        3






        active

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        3 Answers
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        active

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        up vote
        1
        down vote













        HINT



        As noticed we need $x>0$ then



        $$frac{ln sin(x)}{ln tan(x)}=frac{ln frac{sin(x)}x+ln x}{ln frac{tan(x)}x+ln x}$$






        share|cite|improve this answer

























          up vote
          1
          down vote













          HINT



          As noticed we need $x>0$ then



          $$frac{ln sin(x)}{ln tan(x)}=frac{ln frac{sin(x)}x+ln x}{ln frac{tan(x)}x+ln x}$$






          share|cite|improve this answer























            up vote
            1
            down vote










            up vote
            1
            down vote









            HINT



            As noticed we need $x>0$ then



            $$frac{ln sin(x)}{ln tan(x)}=frac{ln frac{sin(x)}x+ln x}{ln frac{tan(x)}x+ln x}$$






            share|cite|improve this answer












            HINT



            As noticed we need $x>0$ then



            $$frac{ln sin(x)}{ln tan(x)}=frac{ln frac{sin(x)}x+ln x}{ln frac{tan(x)}x+ln x}$$







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Nov 16 at 12:07









            gimusi

            85.5k74294




            85.5k74294






















                up vote
                1
                down vote













                Just consider the reciprocal (for $x>0$):



                $$frac{ln tan x}{ln sin x} = frac{ln sin x - ln cos x}{ln sin x} =1- frac{ln cos x}{ln sin x} stackrel{x to 0^+}{longrightarrow} 1$$
                It follows $boxed{lim_{x to 0+} frac{ln sin(x)}{ln tan(x)} = 1}$.






                share|cite|improve this answer



























                  up vote
                  1
                  down vote













                  Just consider the reciprocal (for $x>0$):



                  $$frac{ln tan x}{ln sin x} = frac{ln sin x - ln cos x}{ln sin x} =1- frac{ln cos x}{ln sin x} stackrel{x to 0^+}{longrightarrow} 1$$
                  It follows $boxed{lim_{x to 0+} frac{ln sin(x)}{ln tan(x)} = 1}$.






                  share|cite|improve this answer

























                    up vote
                    1
                    down vote










                    up vote
                    1
                    down vote









                    Just consider the reciprocal (for $x>0$):



                    $$frac{ln tan x}{ln sin x} = frac{ln sin x - ln cos x}{ln sin x} =1- frac{ln cos x}{ln sin x} stackrel{x to 0^+}{longrightarrow} 1$$
                    It follows $boxed{lim_{x to 0+} frac{ln sin(x)}{ln tan(x)} = 1}$.






                    share|cite|improve this answer














                    Just consider the reciprocal (for $x>0$):



                    $$frac{ln tan x}{ln sin x} = frac{ln sin x - ln cos x}{ln sin x} =1- frac{ln cos x}{ln sin x} stackrel{x to 0^+}{longrightarrow} 1$$
                    It follows $boxed{lim_{x to 0+} frac{ln sin(x)}{ln tan(x)} = 1}$.







                    share|cite|improve this answer














                    share|cite|improve this answer



                    share|cite|improve this answer








                    edited Nov 16 at 13:17

























                    answered Nov 16 at 12:17









                    trancelocation

                    8,0561519




                    8,0561519






















                        up vote
                        0
                        down vote













                        The domain of $ln x$ includes all positive values of $x$, so only the right-hand limit exists. If you want to find that, you can use L’Hôpital’s Rule.



                        $$lim_{x to 0} frac{ln(sin x)}{ln(tan x)}$$



                        $$implies frac{frac{1}{sin x}cos x}{frac{1}{tan x}sec^2 x} = frac{tan x}{sin x}cdot frac{cos x}{sec^2 x} = frac{1}{cos x}cdot cos^3 x = cos^2 x$$



                        Now, what does $cos^2 x$ tend to as $x$ tends to $0$?






                        share|cite|improve this answer

























                          up vote
                          0
                          down vote













                          The domain of $ln x$ includes all positive values of $x$, so only the right-hand limit exists. If you want to find that, you can use L’Hôpital’s Rule.



                          $$lim_{x to 0} frac{ln(sin x)}{ln(tan x)}$$



                          $$implies frac{frac{1}{sin x}cos x}{frac{1}{tan x}sec^2 x} = frac{tan x}{sin x}cdot frac{cos x}{sec^2 x} = frac{1}{cos x}cdot cos^3 x = cos^2 x$$



                          Now, what does $cos^2 x$ tend to as $x$ tends to $0$?






                          share|cite|improve this answer























                            up vote
                            0
                            down vote










                            up vote
                            0
                            down vote









                            The domain of $ln x$ includes all positive values of $x$, so only the right-hand limit exists. If you want to find that, you can use L’Hôpital’s Rule.



                            $$lim_{x to 0} frac{ln(sin x)}{ln(tan x)}$$



                            $$implies frac{frac{1}{sin x}cos x}{frac{1}{tan x}sec^2 x} = frac{tan x}{sin x}cdot frac{cos x}{sec^2 x} = frac{1}{cos x}cdot cos^3 x = cos^2 x$$



                            Now, what does $cos^2 x$ tend to as $x$ tends to $0$?






                            share|cite|improve this answer












                            The domain of $ln x$ includes all positive values of $x$, so only the right-hand limit exists. If you want to find that, you can use L’Hôpital’s Rule.



                            $$lim_{x to 0} frac{ln(sin x)}{ln(tan x)}$$



                            $$implies frac{frac{1}{sin x}cos x}{frac{1}{tan x}sec^2 x} = frac{tan x}{sin x}cdot frac{cos x}{sec^2 x} = frac{1}{cos x}cdot cos^3 x = cos^2 x$$



                            Now, what does $cos^2 x$ tend to as $x$ tends to $0$?







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered Nov 16 at 11:59









                            KM101

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